Synergistic insecticidal compositions



' relatively less toxic carbarnates.

United States Patent SYNERGISTIC INSECTICIDAL COMPOSITIONS Howard A. Jones and John A. Garman, Baltimore, Md., and Berton C. Dickinson, Lyndonville, N.Y., assignors to Food Machinery and Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Original application Mar. 24, 1955, Ser. No. 496,596. Divided and this application Oct. 15, 1958, Ser. No. 767,287

2 Claims. (Cl. 167-22) This invention relates broadly to insecticidal compositions, and more particularly to insecticidal compositions containing an organic carbamate acid derivative and 0,0-dimethyl S-l,2 dicarbethoxyethyl) dithiophosphate, hereinafter referred to as Malathion. More particularly, this invention relates to synergistic insecticidal compositions of these compounds wherein the insecticidal effectiveness of each component is enhanced by the presence of the other to produce an unexpected combined effect.

When two or more substances in combination show an unexpectedly high activity, as, for instance, insecticidal activity, the resulting phenomenon is called synergism. The mechanism of synergism is by no means understood. It is, in fact, quite probable that it differs with different synergistic combinations. The term synergism can be defined, however, as a cooperative action which is encountered in combinations of two or more biologically active components in which the combined activity of the two components exceeds the sum of the activities of the components when used alone. The insecticidal activity -of' the mixed components cannot be predicted from known values of the individual components, but is unpredictable and depends on the individual activity of neither.

It is an object of this invention to provide insec t-icidal compositions of enhanced killing power. Another object of this invention is to produce novel compositions con taining compounds capable of synergizing the knock- L,

down and killing properties of individual toxicants. A further object of this invention is to provide compositions including a relatively toxic phosphorus containing insecticide in which superior insecticidal activity is obtained because of the synergistic effects, but in which the ultimate toxicity to warm-blodded animals is greatly reduced because of the lower concentrations of the phosphorus compounds required when used in combination with the Other objects and advantages of the invention will become apparent from the description of the invention set forth below.

According to this invention, there are provided synergistic insecticidal compositions comprising 0,0-dimethyl S-(LZ-dicarbethoxyethyl) dithiophosphate, hereinafter called Malathion, and an organic carbamate ester selected from the group consisting of phenyl N-(3-methoxypropyl)- carbamate and phenyl N-carboxymethylcarbamate. This carbamate may be prepared as described in copending application Ser. No. 812,113, filed May 11, 1959.

The synergistic insecticidal compositions of this invention may be used on a wide variety of insect and mite species, but are particularly effective against such insects as the squash bug and Mexican bean beetle. The combinations are highly effective and economical to use for such large-scale insecticidal requirements as the control of truck crop, forage crop and orchard insects.

The synergistic compositions of this invention can be formulated as aqueous emulsions, as dry or wettable powders, as solutions or in any other suitable vehicle. The insecticidal compositions can be utilized as sprays, as

dusts, as Aerosol mixtures, insecticidal coating compositions, and as residues. In general, they can be applied by methods commonly used for control or eradication of insects, mites and the like. Thus these insecticidal'compositionscan be formulated. with solvents, diluents and carrier,me.dia,,adhesives, spreading, wetting and emulsifying agents and other ingredients.

The relative proportions of the active ingredients as well as inert carriers, solvents, dispersants and the like may vary within wide limits.

Thus the relative proportion (ratio) of the Malathion to the carbamate ester can range from 20 parts of the former per 1 part of the latter to 1 part of the former per 40 parts of the latter and preferably about 1 part of 'the former to about 2 parts of the latter.

. The quantities of the component toxicants in the final insecticidal compositions can range from 0.01% to 25.00% for the Malathion and from 0.05% to 50.00% for the carbamate, and preferably from 0.10% to 10.00% for the Malathion and from 0.10% to 25.00% for the carbamate.

The procedures of the testing methods are described below. The details of the test experiments including the type of formulation and mode of application or dosing, and the species of insects which served as test subjects are given in the examples.

Insects used in the testing included the house fly (M usca domestica L.), Mexican bean beetle (Epilachna varivestis Muls.), pea aphid (Macrosiphum pisi. [Kltb.]), two-spotted spider mite (Tetranychus bimaculatus Harvey), harleqin bug (Murgant'ia histrionica EHahnI) and squash bug (Anasa tristis).

This general method is described in the following reference, Moore, J. Econ. But. 43, No. 2, 188-190 (1950).

The dusting apparatus consists of a vertical glass cylinder, 34 inches high and 8.5 inches in diameter, into which the appropriate dust sample is discharged through a small hole in the center of the cover, by means of a small laboratory duster operating at an air pressure of 4 0 p.s.i.g. The duster assembly comprises a 10 ml. beaker, into which the weighed sample is placed, and fitted with a rubber stopper through which pass the air inlet and dust outlet tubes, both of which are made of 4 inch diameter copper tubing. At the outer end of the air inlet tube is a trigger valve that serves as a control for dispensing the dust. The inner end of this tube reaches nearly to the bottom of the beaker. The end of it is sealed but, along the sides, seven 0.032 inch holes are drilled at irregular intervals which serve as air inlets. Such an arrangement causes pronounced turbulence of the dust and thus insures exhausting the complete sample from the beaker. The dust outlet tube forms an arch from the top of the beaker to the top of the glass dusting tower.

After discharge of the sample into the tower, there is allowed a 2-minute settling time before removal of foliage or insects being treated. A weighed metal plate is placed in the tower each time a test is made, and by weighing the amount of dust deposited on it, it is then possible to calculate the amount applied per acre.

Because of day-to-day variations in the results obtained by this test method, comparisons among the individual components and their combinations were made simultaneously in order to minimize this source of variation.

Slight modifications in this test employed for specific insect species are as noted below.

Mexican bean beetle.-In tests using this insect, bean foliage was dusted then infested with fourth instar Mexican bean beetle larvae. These were allowed to feed for 24 3 H 7 hours, then treated foliage was replaced with untreated. N-carboxymethyl carbamate said components being pres- Mortality records were made at 48 hours. ent in the ratio of about 2 parts of said carbamate ester Squash bug-For this test squash leaves were collected to about 1 part of said dithi'ophosphate. in ,the, field. and, the cut ends of the stem were wrapped 2. A method of killing in's'ects which comprises applyinmoist cotton. Individual leaves were then placed in ing to the insects and their habitata synergistic insecticidal 3.5 inch Petri dishes and dusted as described above. Each composition comprising 0,0-dimethyl S-(1,2-dicarbethtreated leaf was then infested with 10 last instar squash oxyethyl) dithiophosphate and a carbamate ester selected bug nymphs and the covers of the Petri dishes were refrom the group consisting of phenyl-N-(3-methoxyplaced. At the end of 24 hours the treated leaves were propyl)-carbamate and phenyl-N-carboxymethyl carremoved and fresh untreated leaves were introduced into 10 barnate said components being present in the ratio of the dishes. Mortality counts were taken after the bugs about 2 parts of said carbamate ester to about 1 part of had been on the untreated leaves for 24 hours. said dithiophosphate.

Table Carbamate Phosphate R t (Ll as/ Test Method Test Subject Mortality Dust Dust acre) (percent) R Cone. Name Cone.

(Percent) (Percent) 8.0 Dust Tower.-. Mexican Bean Beetle 10 101 do do 0 10.2 80 31.6 0 Malathion. 0. 5 26. 5 0 1 do- 0.5 28.7 80 46.0 0 Malethion 0 25 45. 6 0 do- 0 25 47.3 as

The data in this table demonstrate the unexpected References Cited in the file of this patent effectiveness of the compositions of this invention against UNITED STATES PATENTS t d a mm s as the Mama bean beetle an the Squash :5 2,503,390 Jelinek Apr. 11, 1950 This application is a division of copending application 2679508 Gysm May 1954 Serial No. 496,596, filed March 24, 1955, now abandoned, OTHER REFERENCES which is a continuation-impart of Serial No. 427,374, p med May 3 1954 now abandoned. 40 105mg. USDA Handbook No. 69, May 1954, pp. 105

We clalmi Chemical Age., vol. 63, No. 1631, 1950, p. 540. I. Synergistic insecticidal compositions comprising Sharp: Agn News Letter, 1952, 0,0-dime yl -(h i y y dithiophosphate Roark: USDA Bull. E-344, May 1935, pp. 2-6. and a carbamate ester selected from the group consisting Frear: Chem. of the Pesticides, 3rd ed., January 1955,

of phenyl-N-(3-methoxypropyl)-carbamate and phenyl- PP. 73-91. 

2. A METHOD OF KILLING INSECTS WHICH COMPRISES APPLYCOMPOSITION COMPRISING O,O-DIMETHYL S-(1,2-DICARBETHOXYETHYL) DITHIOPHOSPHATE AND A CARBAMATE ESTER SELECTED FROM THE GROUP CONSISTING OF PHENYL-N-(3-METHOXYPROPYL)-CARBAMATE AND PHENYL-N-CARBOXYMETHYL CARBAMATE SAID COMPONENTS BEING PRESENT IN THE RATIO OF ABOUT 2 PARTS OF SAID CARBAMATE ESTER TO ABOUT 1 PART OF SAID DITHIOPHOSPHATE. 